In the proposed studies an attempt will be made to separate the "bound" pool of cyclic AMP from the "free" pool and examine the effects of drugs and hormones on the pool sizes. Also, a series of antilipolytic compound will be tested for their action of lipolysis, cyclic AMP levels, phosphodiesterase activity, protein kinase and adenylate cyclase activity. An attempt is being made to assay cyclic GMP levels in fat cells with the intention of determining what role, if any, this cyclic nucleotide plays to hormonal control of lipolisis. As previous data have suggested that the lipolytic action of theophylline may be due to same action other than phosphodiesterase inhibition this methyl xanthine will be studied to determine its mechanism of lipolytic action.